A Birmingham area man, two residents of Colbert County and one resident of Tuscaloosa County are the latest believed to have contracted Chikungunya virus, which is rarely deadly but can lead to debilitating joint pain.

The four cases are "preliminary positives" and have not been officially counted yet by the Centers for Disease Control and Prevention, said Kelly Stevens, Alabama Department of Public Health director of epidemiology. But they do represent positive tests for the virus.

All the cases involve travelers picking up the virus in Haiti or other parts of the Caribbean, Stevens said.

Birmingham infectious disease Dr. Mukesh Patel treated the patient in Birmingham and noted the speedy spread of the virus.

"It's a disease that wasn't in the Western Hemisphere until very recently," Patel said. "The first cases detected in the Caribbean were in December, 2013, just seven months ago. And now it has exploded."

Now tens of thousands of cases have been reported in the Caribbean, Central and South America. But as of July 1, a total of 129 Chikungunya cases have been reported in U.S. states and territories. Of those, none have been contracted in the continental U.S. but rather involved travelers returning from infested areas.

The concern is infected travelers will return and get bitten by local mosquitoes, who in turn will bite more humans and spread the virus among U.S. mosquito populations.

"A lot of us believe it's going to happen, it's just a matter of time" before the infections become local, Patel said.

The good news, he said it is that the virus is rarely fatal. But it can, in some patients, leave them with chronic joint pain that's difficult to treat. And even if it's not chronic, the week or so of illness can be brutal, Patel said. He said he treated a healthy young man, who plays basketball recreationally every week and by the fourth day of the illness, he was barely able to walk. They needed a wheelchair to take him to the lab, Patel said.

One of the Colbert County patients was rising senior Kyra Holway, who said her symptoms came on extremely fast, and it has taken about one week for her to feel back to normal, reported WAFF.com. She was on a mission trip where the orphanage they served had an outbreak.

"I was kind of expecting it, because there was an outbreak and I knew I had all the symptoms," Holway said. "I knew there was no treatment, and I knew it would be a good week of not feeling too good."

Stevens said they are stressing that people make sure water vesesels outside are empty. Change the birdbath water regularly, the same with pet watering dishes.When one is infected it is more important than ever to avoid mosquito bites lest they help spread the disease.

Repellent, long sleeves, and long pants are weapons in this battle to not be bitten.

Here's some tips from CDC to avoid bites:

Use air conditioning or window/door screens to keep mosquitoes outside. If you are not able to protect yourself from mosquitoes inside your home or hotel, sleep under a mosquito bed net.

Help reduce the number of mosquitoes outside your home or hotel room by emptying standing water from containers such as flowerpots or buckets.